Comparing mutation sets above Pango lineage roots

[szhan]

One approach to compare the Viridian UShER tree and our pandemic-scale ARG is to examine the sets of mutations occurring directly above the Pango lineage roots. The Viridian UShER tree (v0.4) has 2,131 Pango lineages labelled. We should take a look at the mutation sets for at least the major lineages.